The Maastrichtian is, in the International Commission on Stratigraphy geologic timescale, the latest age of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. From Wikipedia
An exceptionally complete Chorrillo Formation specimen clarifies predator roles in southern Patagonia near the end of the Cretaceous.
